fix: handle bare repos in branch creation and checkout

- Fall back to symbolic-ref when checkout --orphan fails on bare repos\n- Fall back to symbolic-ref when checkout fails on bare repos\n- Make get_current_branch handle bare repos with unborn branches\n- Add integration tests for bare repo branch operations\n\nQuality gates: pytest integration tests (12 passed)

apps/api/src/utils/git_control.py

@@ -124,7 +124,15 @@ def create_branch(repo_path: str, name: str, base_branch: str = "HEAD") -> None:
     try:
         _run_git_command(repo_path, "rev-parse", "--verify", "HEAD^{commit}")
     except RuntimeError:
-        _run_git_command(repo_path, "checkout", "--orphan", name)
+        # No commits yet - empty repository
+        try:
+            _run_git_command(repo_path, "checkout", "--orphan", name)
+        except RuntimeError as e:
+            if "work tree" in str(e).lower():
+                # Bare repository - use symbolic-ref instead
+                _run_git_command(repo_path, "symbolic-ref", "HEAD", f"refs/heads/{name}")
+                return
+            raise
         return
 
     _run_git_command(repo_path, "branch", name, base_branch)
@@ -155,7 +163,14 @@ def checkout_branch(repo_path: str, name: str) -> None:
     Raises:
         RuntimeError: If checkout fails
     """
-    _run_git_command(repo_path, "checkout", name)
+    try:
+        _run_git_command(repo_path, "checkout", name)
+    except RuntimeError as e:
+        if "work tree" in str(e).lower():
+            # Bare repository - use symbolic-ref instead
+            _run_git_command(repo_path, "symbolic-ref", "HEAD", f"refs/heads/{name}")
+            return
+        raise
 
 
 def commit_changes(
@@ -290,6 +305,10 @@ def get_current_branch(repo_path: str) -> str:
         Current branch name
     """
     try:
-        return _run_git_command(repo_path, "rev-parse", "--abbrev-ref", "HEAD").strip()
+        branch = _run_git_command(repo_path, "rev-parse", "--abbrev-ref", "HEAD").strip()
+        if branch != "HEAD":
+            return branch
     except RuntimeError:
-        return _run_git_command(repo_path, "symbolic-ref", "--short", "HEAD").strip()
+        pass
+
+    return _run_git_command(repo_path, "symbolic-ref", "--short", "HEAD").strip()